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>Development with GTK+: widget specific questions</H1
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><A
NAME="AEN709"
>How do I find out about the selection of a GtkList?</A
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><P
>Get the selection something like this:</P
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><PRE
CLASS="PROGRAMLISTING"
>GList *sel;
sel = GTK_LIST(list)-&#62;selection;</PRE
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><P
>This is how GList is defined (quoting glist.h):</P
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><PRE
CLASS="PROGRAMLISTING"
>typedef struct _GList GList;

struct _GList
{
  gpointer data;
  GList *next;
  GList *prev;
};</PRE
></TD
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><P
>A GList structure is just a simple structure for doubly
linked lists. There exist several g_list_*() functions to
modify a linked list in glib.h.  However the
GTK_LIST(MyGtkList)-&#62;selection is maintained by the
gtk_list_*() functions and should not be modified.</P
><P
>The selection_mode of the GtkList determines the
selection facilities of a GtkList and therefore the contents
of GTK_LIST(AnyGtkList)-&#62;selection:</P
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><THEAD
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><TH
><TT
CLASS="LITERAL"
>selection_mode</TT
></TH
><TH
><TT
CLASS="LITERAL"
> GTK_LIST()-&#62;selection</TT
>
contents</TH
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></THEAD
><TBODY
><TR
><TD
><TT
CLASS="LITERAL"
>GTK_SELECTION_SINGLE</TT
></TD
><TD
>selection is either NULL or contains a GList*
pointer for a single selected item.</TD
></TR
><TR
><TD
><TT
CLASS="LITERAL"
>GTK_SELECTION_BROWSE</TT
></TD
><TD
>selection is NULL if the list contains no
widgets, otherwise it contains a GList*
pointer for one GList structure.</TD
></TR
><TR
><TD
><TT
CLASS="LITERAL"
>GTK_SELECTION_MULTIPLE</TT
></TD
><TD
>selection is NULL if no listitems are selected
or a a GList* pointer for the first selected
item. that in turn points to a GList structure
for the second selected item and so
on.</TD
></TR
><TR
><TD
><TT
CLASS="LITERAL"
>GTK_SELECTION_EXTENDED</TT
></TD
><TD
>selection is NULL.</TD
></TR
></TBODY
></TABLE
><P
></P
></DIV
><P
>The data field of the GList structure
GTK_LIST(MyGtkList)-&#62;selection points to the first
GtkListItem that is selected.  So if you would like to
determine which listitems are selected you should go like
this:</P
><TABLE
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WIDTH="100%"
><TR
><TD
><PRE
CLASS="PROGRAMLISTING"
>{
        gchar           *list_items[]={
                                "Item0",
                                "Item1",
                                "foo",
                                "last Item",
                        };
        guint           nlist_items=sizeof(list_items)/sizeof(list_items[0]);
        GtkWidget       *list_item;
        guint           i;

        list=gtk_list_new();
        gtk_list_set_selection_mode(GTK_LIST(list), GTK_SELECTION_MULTIPLE);
        gtk_container_add(GTK_CONTAINER(AnyGtkContainer), list);
        gtk_widget_show (list);

        for (i = 0; i &#60; nlist_items; i++)
        {
                list_item=gtk_list_item_new_with_label(list_items[i]);
                gtk_object_set_user_data(GTK_OBJECT(list_item), (gpointer)i);
                gtk_container_add(GTK_CONTAINER(list), list_item);
                gtk_widget_show(list_item);
        }
}</PRE
></TD
></TR
></TABLE
><P
>To get known about the selection:</P
><TABLE
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WIDTH="100%"
><TR
><TD
><PRE
CLASS="PROGRAMLISTING"
>{
        GList   *items;

        items=GTK_LIST(list)-&#62;selection;

        printf("Selected Items: ");
        while (items) {
                if (GTK_IS_LIST_ITEM(items-&#62;data))
                        printf("%d ", (guint) 
                gtk_object_get_user_data(items-&#62;data));
                items=items-&#62;next;
        }
        printf("\n");
}</PRE
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